Method of fabricating flash memory device

A method of fabricating flash memory devices, comprising the steps of:

• forming a first interlayer insulation film on a semiconductor substrate in which gate and source/drain junctions are formed, and forming a source contact electrically connected to the source junction through the first interlayer insulation film;
• forming a second interlayer insulation film on the first interlayer insulation film and forming a drain contact electrically connected to the drain junction through the second and first interlayer insulation films;
• laminating a stop nitride film and an oxide film on the entire surface including the second interlayer insulation film;
• forming trenches through which the second interlayer insulation film and the drain contact on the source contact are exposed in the stop nitride film and the oxide film;
• forming barrier oxide films on lateral faces of the trenches by an atomic layer deposition method;
• forming a contact hole through which the source contact is exposed in the second interlayer insulation film below the trenches;
• performing a cleaning process;
• and
• burying the trenches and the contact hole with a metal film and forming bit lines connected to the drain contact and source lines connected to the source contact.